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comparison flys-artifacts/src/main/java/de/intevation/flys/artifacts/math/MovingAverage.java @ 4631:d35d316049e8

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A little optimization and handle the case that there are duplicates in the values.
author Sascha L. Teichmann <teichmann@intevation.de>
date Mon, 03 Dec 2012 21:16:15 +0100
parents 63368dcc3f94
children fb9892036bd6
comparison
equal deleted inserted replaced
4630:63368dcc3f94 4631:d35d316049e8
8 public class MovingAverage 8 public class MovingAverage
9 { 9 {
10 10
11 public static double[][] simple(double[][] values, double radius) { 11 public static double[][] simple(double[][] values, double radius) {
12 TreeMap<Double, Double> map = toMap(values); 12 TreeMap<Double, Double> map = toMap(values);
13 double[][] result = new double[values.length][values[0].length]; 13 int N = map.size();
14 double [] xs = new double[N];
15 double [] ys = new double[N];
14 int ndx = 0; 16 int ndx = 0;
15 for (double x: map.keySet()) { 17 for (double x: map.keySet()) {
16 SortedMap<Double, Double> range = 18 SortedMap<Double, Double> range =
17 map.subMap(x-radius, true, x+radius, true); 19 map.subMap(x-radius, true, x+radius, true);
18 double avg = 0d; 20 double avg = 0d;
19 for (Double v: range.values()) { 21 for (double v: range.values()) {
20 avg += v; 22 avg += v;
21 } 23 }
22 avg /= range.size(); 24 avg /= range.size();
23 result[0][ndx] = x; 25 xs[ndx] = x;
24 result[1][ndx] = avg; 26 ys[ndx] = avg;
25 ndx++; 27 ndx++;
26 } 28 }
27 return result; 29 return new double [][] { xs, ys };
28 } 30 }
29 31
30 public static double[][] weighted(double[][] values, double radius) { 32 public static double[][] weighted(double[][] values, double radius) {
31 TreeMap<Double, Double> map = toMap(values); 33 TreeMap<Double, Double> map = toMap(values);
32 double[][] result = new double[values.length][values[0].length]; 34 int N = map.size();
35 double [] xs = new double[N];
36 double [] ys = new double[N];
33 int ndx = 0; 37 int ndx = 0;
38 double _1radius = 1d/radius;
34 for (double x: map.keySet()) { 39 for (double x: map.keySet()) {
35 double avg = 0d; 40 double avg = 0d;
36 double weights = 0d; 41 double weights = 0d;
37 for (Map.Entry<Double, Double> e: 42 for (Map.Entry<Double, Double> e:
38 map.subMap(x-radius, false, x+radius, false).entrySet() 43 map.subMap(x-radius, false, x+radius, false).entrySet()
39 ) { 44 ) {
40 double weight = 1d - Math.abs(x - e.getKey())/radius; 45 double weight = 1d - Math.abs(x - e.getKey())*_1radius;
41 avg += weight*e.getValue(); 46 avg += weight*e.getValue();
42 weights += weight; 47 weights += weight;
43 } 48 }
44 avg /= weights; 49 avg /= weights;
45 result[0][ndx] = x; 50 xs[ndx] = x;
46 result[1][ndx] = avg; 51 ys[ndx] = avg;
47 ndx++; 52 ndx++;
48 } 53 }
49 return result; 54 return new double [][] { xs, ys };
50 } 55 }
51 56
52 private static TreeMap<Double, Double> toMap(double[][] values) { 57 private static TreeMap<Double, Double> toMap(double[][] values) {
53 TreeMap<Double, Double> map = new TreeMap<Double, Double>(); 58 TreeMap<Double, Double> map = new TreeMap<Double, Double>();
54 for(int i = 0; i < values[0].length; i++) { 59 double [] xs = values[0];
55 map.put(values[0][i], values[1][i]); 60 double [] ys = values[1];
61 for (int i = 0; i < xs.length; i++) {
62 map.put(xs[i], ys[i]);
56 } 63 }
57 return map; 64 return map;
58 } 65 }
59 } 66 }
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